1. Field of the Invention
The present invention relates to a thin film for stamper formation, formed on the surface of a patterned resist material, to be used as an electrode for electrocasting of a stamper material, and an electrode material for stamper formation to be used as the material for such an electrode.
2. Description of the Related Art
Optical discs such as a CD and a DVD are mass-produced, using an optical disc original disc called a stamper. FIGS. 8A to 8F show a conventional stamper production method. First, as shown in FIG. 8A, a photoresist film 102 is formed on a glass substrate 101 by spin coating, or the like. Then, as shown in FIG. 8B, the photo resist film 102 is exposed by a laser beam so as to form a latent image 102a. Next, by developing the photo resist film 102, a pattern having a groove part 102b as shown in FIG. 8C is formed. Then, as shown in FIG. 8D, a nickel thin film 103 is formed on the surface of the photo resist film 102 and the glass substrate 101 by a sputtering method, a vapor deposition method, or the like. Thereafter, as shown in FIG. 8E, by applying a nickel electrocasting on the nickel thin film 103 surface, using the nickel thin film 103 as an electrode, a nickel layer 104 is formed. As shown in FIG. 8F, after peeling off the nickel layer 104 from the glass substrate 101, by polishing the upper surface of the nickel layer 104, or the like in FIG. 8F, a stamper 104A can be obtained.
A higher recording density is further required to the optical discs. The expected demand of a high recording density for ensuring a recording capacity of as much as a several tens of GB or more in a 12 cm diameter disc cannot be dealt with by the above-mentioned laser cutting using a laser beam, and thus an electron beam cutting using an electron beam attracts the attention as a method instead of the laser beam cutting. According to the electron beam cutting, a highly fine pattern can be formed compared with the conventional laser beam cutting.
However, in order to execute the electron beam cutting, the electron absorption sensitivity of the resist material should be improved, and thus an electron attractive group such as a chlorine, a sulfur, and a fluorine, or the like is introduced into the resist material. However, it was revealed that a problem of the stamper quality deterioration arises by the damage of the nickel thin film due to reaction of the electron attractive group in the resist material and the nickel thin film at the time of applying the nickel electrocasting.
Accordingly, an object of the present invention is to provide a production method for an optical disc, capable of obtaining a good S/N ratio without deterioration of the stamper quality due to reaction with an electron attractive group contained in a resist material.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Ru element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented. Moreover, since the electrode can be formed with the excellent flatness, the S/N ratio of the optical disc can be improved.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Cu element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as P element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Mg element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Cr element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented. Moreover, since the electrode can be formed with the excellent flatness, the S/N ratio of the optical disc can be improved.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Au element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Si element by less than 25% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Ti element by less than 50% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented.
A production method for an optical disc according to the present invention comprises the processes of forming a resist film on a substrate, patterning the resist film on the substrate by an electron beam cutting, forming an electrode on the patterned resist film, forming a metal layer on the electrode by the electrocasting, and injection molding of a resin, using the metal layer peeled off from the electrode as a stamper, wherein the electrode contains Ni element as the main component as well as Ag element by less than 50% by weight.
According to the production method for an optical disc, since reaction of Ni in the electrode material and an electron attractive group contained in the resist material can be restrained, the stamper quality deterioration can be prevented. Moreover, since the electrode can be formed with the excellent flatness, the S/N ratio of the optical disc can be improved.
The metal layer can be made of nickel. Moreover, the metal layer can also be made of nickel alloy.
Although the reference numerals in the accompanied drawings are applied in the parentheses in order to facilitate understanding of the present invention, the present invention is not limited to the embodiment shown in the figures thereby.